I posted about my 32 inch Toshiba TV with the squatty bodied, cone headed
picture with the three inch black band across the bottom. Thanks to the
excellent advice that I received here, I sent away for a dozen or so, high
temp caps for the vertical section and the surrounding area of the board.
I'm a rookie and was mostly worried about getting zapped. That didn't happen
and I was able to unsolder the caps using Rat Shack wick. It worked pretty
good but was rather tedious. In fact I only used about half the caps that I
ordered. I started to resolder the IC, but thought better of it when the
solder started to run down each connection and wanted to ooze together. I
guess one is supposed to totally remove all of the old solder and then redo
it. I also almost messed up a trace by trying to bend the leg of a cap
straight before cutting it off. In retrospect, I see how stupid that was. It
didn't break but did lift off of the board slightly. The trace was at the
edge of a part of the circuit and I could have duplicated the path to the
next component by soldering a small wire between them. I was wondering if I
should have tacked it down with a drop of Super Glue or maybe a small dab of
hot melt. Anywhooooo .... plugged it all back up and hit the switch and,
bada bing ... works like a charm! I put the cover back on and gave it a good
bouncing and shaking to make sure nothing was ready to come loose. I then
left it on for over 24 hours ... still fine. The worst part of the whole
thing is a sore back from lugging it our to the garage and back.

While doing some reading on caps, one maker's page said, "do not
straighten caps, that are soldered into place." Am I the only person here
that can't seem to resist? It's like not squeezing a black head.
The only other minor problem that I ran into was, a small cap without any
kind of polarity marking and nothing on the board. I reinstalled that one.
How common are those?

Well, needless to say, I'm glad that I didn't just toss the TV in the trash.
I wasn't about to lug that monster down to some shop, owner unknown, and pay
to have it fixed. It's a 1994 model ... not something that one wants to sink
a lot of money into. Hard to believe that just a few dollars in caps made it
right as rain. Thanks again, for all of the help.

"Forrest" wrote in message
...
I posted about my 32 inch Toshiba TV with the squatty bodied, cone headed
picture with the three inch black band across the bottom. Thanks to the
excellent advice that I received here, I sent away for a dozen or so, high
temp caps for the vertical section and the surrounding area of the board.
I'm a rookie and was mostly worried about getting zapped. That didn't
happen and I was able to unsolder the caps using Rat Shack wick. It worked
pretty good but was rather tedious. In fact I only used about half the caps
that I ordered. I started to resolder the IC, but thought better of it when
the solder started to run down each connection and wanted to ooze together.
I guess one is supposed to totally remove all of the old solder and then
redo it. I also almost messed up a trace by trying to bend the leg of a cap
straight before cutting it off. In retrospect, I see how stupid that was.
It didn't break but did lift off of the board slightly. The trace was at
the edge of a part of the circuit and I could have duplicated the path to
the next component by soldering a small wire between them. I was wondering
if I should have tacked it down with a drop of Super Glue or maybe a small
dab of hot melt. Anywhooooo .... plugged it all back up and hit the switch
and, bada bing ... works like a charm! I put the cover back on and gave it
a good bouncing and shaking to make sure nothing was ready to come loose. I
then left it on for over 24 hours ... still fine. The worst part of the
whole thing is a sore back from lugging it our to the garage and back.

While doing some reading on caps, one maker's page said, "do not
straighten caps, that are soldered into place." Am I the only person here
that can't seem to resist? It's like not squeezing a black head.
The only other minor problem that I ran into was, a small cap without any
kind of polarity marking and nothing on the board. I reinstalled that one.
How common are those?

Well, needless to say, I'm glad that I didn't just toss the TV in the
trash. I wasn't about to lug that monster down to some shop, owner
unknown, and pay to have it fixed. It's a 1994 model ... not something
that one wants to sink a lot of money into. Hard to believe that just a
few dollars in caps made it right as rain. Thanks again, for all of
the help.


Glad you got a result, and we were all able to help you along the way. There
is no real 'trick' to neat soldering, just lots of practice, and the right
tools. For soldering IC pins and general joints of the sorts of sizes and
density that you will see on the average TV board, you need an iron of
between about 25 and 40 watts, with either a pencil tip, or a chisel tip, no
more than about 2mm across the flat. The solder doesn't want to be much more
than 0.7mm diameter for most general work. When reworking joints such as
those on the chip that you started on, lay the tip's flat, or side of the
pencil point tip, against the side of the existing joint, until it melts
nicely. Then, with the iron still aginst the pin, feed in a tiny amount of
new solder to the opposite side of the joint. Just enough to make the joint
look clean and shiny again (we're not talking lead-free joints here, of
course ...!) and not so much that the joint 'floods' and starts to run. The
solder should stay completely confined to the joint. If it tries to bridge
the gap to the next pin, then you've got too much on there, and you need to
wick off and start again.

I must admit that if I see a cap in the area that I'm working in that isn't
straight, I do have a pedantic tendency to apply the iron to its legs, and
make it back into a proper upright little soldier ...

There are all sorts of caps of lower values that have no polarity. As a rule
of thumb, all electrolytics have polarity. There is one exception to this,
and that is the bipolar electrolytic. You do come across them being used as
coupling caps, particularly in audio gear, but even then they are fairly
rare compared to the very common polarised type.

Arfa

Greetings Arfa & others..

Regarding:
" There are all sorts of caps of lower values that have no polarity.
As a rule
| of thumb, all electrolytics have polarity. There is one exception to
this,
| and that is the bipolar electrolytic. You do come across them being
used as
| coupling caps, particularly in audio gear, but even then they are
fairly
| rare compared to the very common polarised type."


Not all that uncommon or rare. I've even got them in my AT&T fixed
line telephone.

Reference:
http://www.mouser.com/search/Refine....&N s=P_SField

Especially note under, Product:
Bi-Polar/Non-Polar Electrolytic Capacitors

Pick a value and click on the Apply Filters button. Take a look at any
of your major electronics component distributors, they'll have a
variety of them.

Cheers,
Mr. Mentor



"Arfa Daily" wrote in message
...
|
| "Forrest" wrote in message
| ...
| I posted about my 32 inch Toshiba TV with the squatty bodied, cone
headed
| picture with the three inch black band across the bottom. Thanks to
the
| excellent advice that I received here, I sent away for a dozen or
so, high
| temp caps for the vertical section and the surrounding area of the
board.
| I'm a rookie and was mostly worried about getting zapped. That
didn't
| happen and I was able to unsolder the caps using Rat Shack wick. It
worked
| pretty good but was rather tedious. In fact I only used about half
the caps
| that I ordered. I started to resolder the IC, but thought better of
it when
| the solder started to run down each connection and wanted to ooze
together.
| I guess one is supposed to totally remove all of the old solder and
then
| redo it. I also almost messed up a trace by trying to bend the leg
of a cap
| straight before cutting it off. In retrospect, I see how stupid
that was.
| It didn't break but did lift off of the board slightly. The trace
was at
| the edge of a part of the circuit and I could have duplicated the
path to
| the next component by soldering a small wire between them. I was
wondering
| if I should have tacked it down with a drop of Super Glue or maybe
a small
| dab of hot melt. Anywhooooo .... plugged it all back up and hit the
switch
| and, bada bing ... works like a charm! I put the cover back on and
gave it
| a good bouncing and shaking to make sure nothing was ready to come
loose. I
| then left it on for over 24 hours ... still fine. The worst part of
the
| whole thing is a sore back from lugging it our to the garage and
back.
|
| While doing some reading on caps, one maker's page said, "do
not
| straighten caps, that are soldered into place." Am I the only
person here
| that can't seem to resist? It's like not squeezing a black head.
| The only other minor problem that I ran into was, a small cap
without any
| kind of polarity marking and nothing on the board. I reinstalled
that one.
| How common are those?
|
| Well, needless to say, I'm glad that I didn't just toss the TV in
the
| trash. I wasn't about to lug that monster down to some shop, owner
| unknown, and pay to have it fixed. It's a 1994 model ... not
something
| that one wants to sink a lot of money into. Hard to believe that
just a
| few dollars in caps made it right as rain. Thanks again, for
all of
| the help.
|
|
| Glad you got a result, and we were all able to help you along the
way. There
| is no real 'trick' to neat soldering, just lots of practice, and the
right
| tools. For soldering IC pins and general joints of the sorts of
sizes and
| density that you will see on the average TV board, you need an iron
of
| between about 25 and 40 watts, with either a pencil tip, or a chisel
tip, no
| more than about 2mm across the flat. The solder doesn't want to be
much more
| than 0.7mm diameter for most general work. When reworking joints
such as
| those on the chip that you started on, lay the tip's flat, or side
of the
| pencil point tip, against the side of the existing joint, until it
melts
| nicely. Then, with the iron still aginst the pin, feed in a tiny
amount of
| new solder to the opposite side of the joint. Just enough to make
the joint
| look clean and shiny again (we're not talking lead-free joints here,
of
| course ...!) and not so much that the joint 'floods' and starts to
run. The
| solder should stay completely confined to the joint. If it tries to
bridge
| the gap to the next pin, then you've got too much on there, and you
need to
| wick off and start again.
|
| I must admit that if I see a cap in the area that I'm working in
that isn't
| straight, I do have a pedantic tendency to apply the iron to its
legs, and
| make it back into a proper upright little soldier ...
|
| There are all sorts of caps of lower values that have no polarity.
As a rule
| of thumb, all electrolytics have polarity. There is one exception to
this,
| and that is the bipolar electrolytic. You do come across them being
used as
| coupling caps, particularly in audio gear, but even then they are
fairly
| rare compared to the very common polarised type.
|
| Arfa
|
|

"dBc" wrote in message
...
Greetings Arfa & others..

Regarding:
" There are all sorts of caps of lower values that have no polarity.
As a rule
| of thumb, all electrolytics have polarity. There is one exception to
this,
| and that is the bipolar electrolytic. You do come across them being
used as
| coupling caps, particularly in audio gear, but even then they are
fairly
| rare compared to the very common polarised type."


Not all that uncommon or rare. I've even got them in my AT&T fixed
line telephone.

Reference:
http://www.mouser.com/search/Refine....&N s=P_SField

Especially note under, Product:
Bi-Polar/Non-Polar Electrolytic Capacitors

Pick a value and click on the Apply Filters button. Take a look at any
of your major electronics component distributors, they'll have a
variety of them.

Cheers,
Mr. Mentor

I don't dispute that they exist in suppliers' catalogues, nor that they are
used occasionally in a variety of kit, but I think that anyone in the repair
business would agree with me that they are "fairly rare" in day to day
encounters with most consumer equipment of average quality and design. I
thought that was what I was conveying by using that phrase. Perhaps I should
have said "comparitively rare". To qualify that, I have in stock perhaps 500
polarised electrolytic caps of maybe 30 different values. I use them on a
daily basis. Compare this to 5 each of two different values of bipolar
electrolytic. The last time I used one was probably 3 months ago in a
Musical Fidelity preamp (very expensive, and in my opinion not very well
designed).

If you took 20 'average' service engineers, and asked them what a bipolar
electrolytic was, I'm willing to bet that probably seven or eight of them
would never even have heard of them, and fifteen or more would never have
replaced one, or had any in stock.

As for them being in a telephone, that is a bit of a special case, with lots
of high level AC voice signals, floating on high DC levels. With signals
like this flying around inside, any coupling cap that needs to be big enough
to have to be an electrolytic, will of course need to be bipolar ...

Arfa

Arfa..

With the spelling as "polarised type" you may also be in the U.K or
Australia...

Perhaps they're not all that common over there, here in the U.S. they
show up in a variety of consumer and non-consumer products. Further,
as illustrated by Mouser, they're not that specialized. No doubt that
they aren't used as much as aluminum polarized electrolytic
capacitors, but they show up in a variety of various electronics these
days. If they didn't, the good folks at Mouser would have absolutely
no reason to carry the variety of assortments they currently stock.
Which further implies that there is a demand for them.

Cheers,
Mr. Mentor



"Arfa Daily" wrote in message
...
|
| "dBc" wrote in message
| ...
| Greetings Arfa & others..
|
| Regarding:
| " There are all sorts of caps of lower values that have no
polarity.
| As a rule
| | of thumb, all electrolytics have polarity. There is one
exception to
| this,
| | and that is the bipolar electrolytic. You do come across them
being
| used as
| | coupling caps, particularly in audio gear, but even then they
are
| fairly
| | rare compared to the very common polarised type."
|
|
| Not all that uncommon or rare. I've even got them in my AT&T fixed
| line telephone.
|
| Reference:
|
http://www.mouser.com/search/Refine....&N s=P_SField
|
| Especially note under, Product:
| Bi-Polar/Non-Polar Electrolytic Capacitors
|
| Pick a value and click on the Apply Filters button. Take a look at
any
| of your major electronics component distributors, they'll have a
| variety of them.
|
| Cheers,
| Mr. Mentor
|
| I don't dispute that they exist in suppliers' catalogues, nor that
they are
| used occasionally in a variety of kit, but I think that anyone in
the repair
| business would agree with me that they are "fairly rare" in day to
day
| encounters with most consumer equipment of average quality and
design. I
| thought that was what I was conveying by using that phrase. Perhaps
I should
| have said "comparitively rare". To qualify that, I have in stock
perhaps 500
| polarised electrolytic caps of maybe 30 different values. I use them
on a
| daily basis. Compare this to 5 each of two different values of
bipolar
| electrolytic. The last time I used one was probably 3 months ago in
a
| Musical Fidelity preamp (very expensive, and in my opinion not very
well
| designed).
|
| If you took 20 'average' service engineers, and asked them what a
bipolar
| electrolytic was, I'm willing to bet that probably seven or eight of
them
| would never even have heard of them, and fifteen or more would never
have
| replaced one, or had any in stock.
|
| As for them being in a telephone, that is a bit of a special case,
with lots
| of high level AC voice signals, floating on high DC levels. With
signals
| like this flying around inside, any coupling cap that needs to be
big enough
| to have to be an electrolytic, will of course need to be bipolar ...
|
| Arfa
|
|

| I don't dispute that they exist in suppliers' catalogues, nor that
they are
| used occasionally in a variety of kit, but I think that anyone in
the repair
| business would agree with me that they are "fairly rare" in day to
day
| encounters with most consumer equipment of average quality and
design. I
| thought that was what I was conveying by using that phrase. Perhaps
I should
| have said "comparitively rare". To qualify that, I have in stock
perhaps 500
| polarised electrolytic caps of maybe 30 different values. I use them
on a
| daily basis. Compare this to 5 each of two different values of
bipolar
| electrolytic. The last time I used one was probably 3 months ago in
a
| Musical Fidelity preamp (very expensive, and in my opinion not very
well
| designed).
|
| If you took 20 'average' service engineers, and asked them what a
bipolar
| electrolytic was, I'm willing to bet that probably seven or eight of
them
| would never even have heard of them, and fifteen or more would never
have
| replaced one, or had any in stock.
|
| As for them being in a telephone, that is a bit of a special case,
with lots
| of high level AC voice signals, floating on high DC levels. With
signals
| like this flying around inside, any coupling cap that needs to be
big enough
| to have to be an electrolytic, will of course need to be bipolar ...
|
| Arfa
|
|


"dBc" wrote in message
...
Arfa..

With the spelling as "polarised type" you may also be in the U.K or
Australia...

Perhaps they're not all that common over there, here in the U.S. they
show up in a variety of consumer and non-consumer products. Further,
as illustrated by Mouser, they're not that specialized. No doubt that
they aren't used as much as aluminum polarized electrolytic
capacitors, but they show up in a variety of various electronics these
days. If they didn't, the good folks at Mouser would have absolutely
no reason to carry the variety of assortments they currently stock.
Which further implies that there is a demand for them.

Cheers,
Mr. Mentor

You are correct that I am in the UK. I am frankly amazed at the quantity of
these devices that Mouser apparantly stock - although it has to be said that
they appear to be endlessly duplicating effectively the same product from a
lot of different manufacturers, but in slight variations of case style etc.
Digikey seem to also keep a good range, but nothing like as many as Mouser.

Looking at Farnell's website (they are probably the joint biggest supplier
of electronic components in the UK) turns up just 22 items spread across a
limited range of 12 values. A similar search of RS Components (the other
joint biggest supplier) turned up just 35 items spread across 14 values.
Contrast this with 9154 entries at Farnell, and 3898 entries at RS for
normal polarised types. Applying the same logic as yours for Mouser, if
there was a big demand for them here, the two biggest suppliers of
components to both the domestic and industrial repair industries, would have
every reason to stock them in much bigger quantities / varieties?

Compared to polarised types, I definitely see these devices only used in
very limited applications here such as coupling caps in some high end audio,
caps in speaker cross-overs, and sometimes as the coupling caps in voltage
multipliers for VFDs or as coupling caps for the filament supply on VFDs. I
can't actually think of many other applications where I would expect to see
them.

I would think that most of the consumer equipment that we see here in the
UK, comes from the same Japanese / Korean / Chinese stables as that which
appears in the US, so I am a little puzzled as to why you seem to see,
apparently, so many more of these devices in use in equipment over there.

It's an interesting observation. Can you elaborate as to what equipment you
see a lot of them in and in which bits of circuitry ? Also, what is your
experiences of them failing ? Has anyone else in any other parts of the
world got any observations on this ?

Arfa

Greetings Arfa & others..

Regarding:
"It's an interesting observation. Can you elaborate as to what
equipment you
see a lot of them in and in which bits of circuitry ? Also, what is
your
experiences of them failing ? Has anyone else in any other parts of
the
world got any observations on this ?"

As previously mentioned, I've got several of them in an elaborate AT&T
telephone that I've got here beside me. How do I know this? Sure
enough, after about 10 years the phone started revealing a "BUZZZZ" on
digitally recorded messages and, conversely playing those messages
back. In fact, it was so bad that parts of the playback would be
overcome in buzz or interrupted & blank. As expected the aluminized
electrolytics were suspect. High ESR readings on many of them revealed
that they were just getting hot in addition to their age in an area of
more than warm DC voltage regulators. Both polarized and non-polarized
are used in the circuitry. In fact, I've also seen this with various
two-way equipment in addition to various audio equipment. Obviously,
the audio applications can be in any type of electronics that passes
or processes audio. Electrolytics, by their nature whether polarized
or non-polarized tend to age and eventually dry up resulting in high
ESR readings or poorly filtered signal/DC paths. It's for this reason
that when I DO go back in to replace them, I absolutely insist on 105C
parts. I don't even bother looking at the 85C parts anymore. I find it
a bit disheartening to find (as I'm sure you've seen all TOO many
times) at 6WVDC electrolytic on a 5V DC line. Talk about design-wise
penny-pinching to an absolute extreme! I cringe when I see this in a
[rather] expensive piece of electronics and replace them (when needed)
with a capacitor with at least a 16WVDC rating at 105C.

I will grant you that we are rather spoiled over here in the states
when it comes to component suppliers. After growing up in San Jose,
CA. and calling Silicon Valley my home for more years that I care to
divulge, we also tend to create a great number of designs &
components. As you've mentioned, unfortunately in many ways, those
designs are now days being forwarded along with manufacturing etc. to
Taiwan & mainland China. In addition, there are MANY other countries
that are now receiving such manufacturing plants and major operations.
It seems that the domestic corporate decision makers for high
technology want to do it ANYWHERE but here in the states these days..
Don't get me started on this as I'll end up writing a dissertation on
the subject!

Since Mouser isn't all that far away and their catalog is sporting no
less than 1490 pages with no minimum order, I tend to gravitate to
them first. In addition, I've had the unfortunate experience here of
late of ordering some electrolytics (polarized types) for the
motherboard that I'm using right now. A quick background on that.. The
previous owner noticed that it was resetting all the time and a quick
glance revealed the infamous GSC capacitors out of Taiwan where the
electrolyte formula was [supposedly] stolen for local manufacturing
efforts. Apparently, they thought they could reproduce what the
Japanese take pride in doing for substantially less money.
Unfortunately, as later revealed by a multitude of failing
motherboards from various manufacturers, the formula wasn't quite
right... Result, most of the Taiwanese motherboard manufacturers are
now incorporating excellent quality Japanese components (electrolytic
capacitors) as they *should* have done from the beginning! Trying to
save a few pennies resulted in a major black eye to the Taiwanese
motherboard industry there for a while! I ordered some of those needed
electrolytics from Mouser but, unfortunately, at 5mm L.S. In fact,
what I *really* needed was 3mm L.S. I called Mouser and fully admitted
that this wasn't their fault but mine! They said, no problem, we'll
send the 3mm components to you immediately. I asked, what address to I
send these 5mm parts back to, they replied, don't worry about it -
just keep them. I've been rather satisfied with them ever since.
Further, the ladies at the order desk are absolutely delightful to
chat with on the phone - they just want to make you happy and get you
the components you need. What I [typically] find is they've got
*exactly* the components you need and in the off chance they don't,
they'll point you to who does have them. Of course, crossing a foreign
component over to the "American" equivalent often has to be done -
which can be a challenge in and of itself! But once done, I have found
Mouser typically has the component.

Cheers,
Mr. Mentor



"Arfa Daily" wrote in message
...
|
|
| | I don't dispute that they exist in suppliers' catalogues, nor
that
| they are
| | used occasionally in a variety of kit, but I think that anyone
in
| the repair
| | business would agree with me that they are "fairly rare" in day
to
| day
| | encounters with most consumer equipment of average quality and
| design. I
| | thought that was what I was conveying by using that phrase.
Perhaps
| I should
| | have said "comparitively rare". To qualify that, I have in stock
| perhaps 500
| | polarised electrolytic caps of maybe 30 different values. I use
them
| on a
| | daily basis. Compare this to 5 each of two different values of
| bipolar
| | electrolytic. The last time I used one was probably 3 months ago
in
| a
| | Musical Fidelity preamp (very expensive, and in my opinion not
very
| well
| | designed).
| |
| | If you took 20 'average' service engineers, and asked them what
a
| bipolar
| | electrolytic was, I'm willing to bet that probably seven or
eight of
| them
| | would never even have heard of them, and fifteen or more would
never
| have
| | replaced one, or had any in stock.
| |
| | As for them being in a telephone, that is a bit of a special
case,
| with lots
| | of high level AC voice signals, floating on high DC levels. With
| signals
| | like this flying around inside, any coupling cap that needs to
be
| big enough
| | to have to be an electrolytic, will of course need to be bipolar
....
| |
| | Arfa
| |
| |
|
|
| "dBc" wrote in message
| ...
| Arfa..
|
| With the spelling as "polarised type" you may also be in the U.K
or
| Australia...
|
| Perhaps they're not all that common over there, here in the U.S.
they
| show up in a variety of consumer and non-consumer products.
Further,
| as illustrated by Mouser, they're not that specialized. No doubt
that
| they aren't used as much as aluminum polarized electrolytic
| capacitors, but they show up in a variety of various electronics
these
| days. If they didn't, the good folks at Mouser would have
absolutely
| no reason to carry the variety of assortments they currently
stock.
| Which further implies that there is a demand for them.
|
| Cheers,
| Mr. Mentor
|
| You are correct that I am in the UK. I am frankly amazed at the
quantity of
| these devices that Mouser apparantly stock - although it has to be
said that
| they appear to be endlessly duplicating effectively the same product
from a
| lot of different manufacturers, but in slight variations of case
style etc.
| Digikey seem to also keep a good range, but nothing like as many as
Mouser.
|
| Looking at Farnell's website (they are probably the joint biggest
supplier
| of electronic components in the UK) turns up just 22 items spread
across a
| limited range of 12 values. A similar search of RS Components (the
other
| joint biggest supplier) turned up just 35 items spread across 14
values.
| Contrast this with 9154 entries at Farnell, and 3898 entries at RS
for
| normal polarised types. Applying the same logic as yours for Mouser,
if
| there was a big demand for them here, the two biggest suppliers of
| components to both the domestic and industrial repair industries,
would have
| every reason to stock them in much bigger quantities / varieties?
|
| Compared to polarised types, I definitely see these devices only
used in
| very limited applications here such as coupling caps in some high
end audio,
| caps in speaker cross-overs, and sometimes as the coupling caps in
voltage
| multipliers for VFDs or as coupling caps for the filament supply on
VFDs. I
| can't actually think of many other applications where I would expect
to see
| them.
|
| I would think that most of the consumer equipment that we see here
in the
| UK, comes from the same Japanese / Korean / Chinese stables as that
which
| appears in the US, so I am a little puzzled as to why you seem to
see,
| apparently, so many more of these devices in use in equipment over
there.
|
| It's an interesting observation. Can you elaborate as to what
equipment you
| see a lot of them in and in which bits of circuitry ? Also, what is
your
| experiences of them failing ? Has anyone else in any other parts of
the
| world got any observations on this ?
|
| Arfa
|
|